Count Makashi
Count Dookus number 1 fan
I didn't say it changes everything, it was still some good left in him.
In Dark Rendezvous, Yoda almost turned Dooku back to the light side and probably he would seceded, if Anakin hadn't come, because of this Dooku become jealous and angry. In Dark Rendezvous he seams to regret turning to the Dark Side, but his pride, to becoming the most powerful jedi, is what holds him to the Dark side and his belief in Sidious.
There was always a risk, talking with Sidious. Sometimes the conversation would go badly, and Dooku would fail to please somehow. It was a terrible thing, failing to please his Master(Sidious).
I have dealt out your deaths, your schemes, your betrayals. I have paid for your war with my time, my riches, my friends, and my honor.»
Dooku to Sidious
Dooku believed in Sidious and to be betrayed like that, he could have betrayed him back, that is a way of the Sith, the Dark side, but i guess it wouldn't suit Dookus character, he is not a snitch.